Semi-Annual Consolidated Balance Sheet
| Concept | As at 2024-04-30 | As at 2024-04-30 | As at 2024-04-30 | As at 2024-04-30 | As at 2024-04-30 | As at 2024-04-30 | As at 2024-04-30 | As at 2024-04-30 | As at 2024-04-30 | As at 2024-04-30 | As at 2024-04-30 | As at 2024-04-30 | As at 2024-04-30 | As at 2024-04-30 | As at 2024-04-30 | As at 2024-04-30 | As at 2024-04-30 | As at 2024-04-30 | As at 2024-04-30 | As at 2024-04-30 | As at 2024-04-30 | As at 2024-04-30 | As at 2024-04-30 | As at 2024-04-30 | As at 2023-04-30 | As at 2023-04-30 | As at 2023-04-30 | As at 2023-04-30 | As at 2023-04-30 | As at 2023-04-30 | As at 2023-04-30 | As at 2023-04-30 | As at 2023-04-30 | As at 2023-04-30 | As at 2023-04-30 | As at 2023-04-30 | As at 2023-04-30 | As at 2023-04-30 | As at 2023-04-30 | As at 2023-04-30 | As at 2023-04-30 | As at 2023-04-30 | As at 2023-04-30 | As at 2023-04-30 | As at 2023-04-30 | As at 2023-04-30 | As at 2023-04-30 | As at 2023-04-30 | As at 2022-04-30 | As at 2022-04-30 | As at 2022-04-30 | As at 2022-04-30 | As at 2022-04-30 | As at 2022-04-30 | As at 2022-04-30 | As at 2022-04-30 | As at 2022-04-30 | As at 2022-04-30 | As at 2022-04-30 | As at 2022-04-30 | As at 2022-04-30 | As at 2022-04-30 | As at 2022-04-30 | As at 2022-04-30 | As at 2022-04-30 | As at 2022-04-30 | As at 2022-04-30 | As at 2022-04-30 | As at 2022-04-30 | As at 2022-04-30 | As at 2022-04-30 | As at 2022-04-30 | 
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Semi-annual consolidated balance sheet | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Balance sheet | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Assets | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Current assets | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Cash and deposits | — | — | — | — | — | 
                                                1,718,384,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                831,167,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                968,367,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                1,754,091,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Other | — | — | — | — | — | 
                                                211,225,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                78,948,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                90,586,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                152,372,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Allowance for doubtful accounts | — | — | — | — | — | 
                                                -27,422,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -14,047,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                -2,797,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -18,402,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Current assets | — | — | — | — | — | 
                                                3,932,203,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,602,082,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                2,659,311,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                3,826,238,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Non-current assets | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Property, plant and equipment | — | — | — | — | — | 
                                                1,766,415,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,646,900,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                1,649,267,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                1,763,560,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Property, plant and equipment | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Buildings and structures | — | — | — | — | — | 
                                                3,158,591,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                2,916,116,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Accumulated depreciation | — | — | — | — | — | 
                                                -1,696,399,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                -1,620,067,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Accumulated impairment | — | — | — | — | — | 
                                                -480,518,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                -480,518,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Buildings and structures, net | — | — | — | — | — | 
                                                981,673,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                815,530,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Machinery, equipment and vehicles | — | — | — | — | — | 
                                                3,629,263,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                3,496,590,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Accumulated depreciation | — | — | — | — | — | 
                                                -3,146,489,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                -2,985,246,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Accumulated impairment | — | — | — | — | — | 
                                                -260,133,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                -260,445,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Machinery, equipment and vehicles, net | — | — | — | — | — | 
                                                222,640,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                250,897,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Land | — | — | — | — | — | 
                                                475,757,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                391,263,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                447,409,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                521,684,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Construction in progress | — | — | — | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                88,030,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                88,030,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Other | — | — | — | — | — | 
                                                25,247,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                19,356,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                24,405,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                25,247,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Accumulated depreciation | — | — | — | — | — | 
                                                -5,890,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                -841,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Other, net | — | — | — | — | — | 
                                                19,356,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                24,405,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Intangible assets | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Other | — | — | — | — | — | 
                                                10,513,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,246,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                3,020,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                14,941,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Intangible assets | — | — | — | — | — | 
                                                21,406,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                14,138,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                26,223,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                38,144,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Investments and other assets | — | — | — | — | — | 
                                                3,099,570,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,333,627,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                3,650,045,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                3,443,930,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Investments and other assets | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Investment securities | — | — | — | — | — | 
                                                3,005,985,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,001,685,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                3,197,584,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                3,215,193,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Long-term loans receivable | — | — | — | — | — | 
                                                3,989,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                753,971,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                733,971,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                47,042,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Other | — | — | — | — | — | 
                                                89,904,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                83,325,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                166,896,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                206,492,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Allowance for doubtful accounts | — | — | — | — | — | 
                                                -308,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -685,971,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                -677,196,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -24,798,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Non-current assets | — | — | — | — | — | 
                                                4,887,392,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                4,994,666,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                5,325,536,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                5,245,634,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Assets | — | — | — | — | — | 
                                                8,819,595,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                7,596,749,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                7,984,847,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                9,071,873,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Liabilities | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Current liabilities | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Notes and accounts payable - trade | — | — | — | — | — | 
                                                464,571,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                588,033,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Short-term borrowings | — | — | — | — | — | 
                                                380,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                300,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                300,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                340,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Income taxes payable | — | — | — | — | — | 
                                                112,948,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                108,661,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                6,131,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                7,832,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Other | — | — | — | — | — | 
                                                33,498,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                33,188,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                21,960,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                22,278,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Current liabilities | — | — | — | — | — | 
                                                1,576,247,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,226,783,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                1,269,194,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                1,508,586,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Non-current liabilities | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Long-term borrowings | — | — | — | — | — | 
                                                1,128,772,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                900,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                1,050,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                1,383,994,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Retirement benefit liability | — | — | — | — | — | 
                                                35,129,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                28,816,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Asset retirement obligations | — | — | — | — | — | 
                                                9,242,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                9,242,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                10,860,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                10,860,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Other | — | — | — | — | — | 
                                                19,996,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                18,741,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                24,229,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                25,332,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Non-current liabilities | — | — | — | — | — | 
                                                2,855,372,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,045,692,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                2,042,846,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                2,940,913,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Liabilities | — | — | — | — | — | 
                                                4,431,619,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,272,476,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                3,312,040,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                4,449,500,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Provision for retirement benefits for directors (and other officers) | — | — | — | — | — | 
                                                425,918,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                425,918,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                416,184,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                416,184,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Provision for bonuses | — | — | — | — | — | 
                                                36,369,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                32,369,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                41,408,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                41,408,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Deferred tax liabilities | — | — | — | — | — | 
                                                447,549,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                432,975,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                421,148,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                444,715,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Net assets | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Shareholders' equity | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Share capital | — | — | — | — | — | 
                                                1,303,843,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,303,843,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                1,303,843,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                1,303,843,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Capital surplus | — | — | — | — | — | 
                                                1,988,608,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,198,003,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                1,198,003,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                1,533,904,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Retained earnings | — | — | — | — | — | 
                                                270,018,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,091,185,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                1,501,457,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                1,088,106,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Treasury shares | — | — | — | — | — | 
                                                -198,939,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -198,939,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                -198,939,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -198,939,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Shareholders' equity | — | — | — | — | — | 
                                                3,363,531,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,394,092,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                3,804,365,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                3,726,914,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Valuation and translation adjustments | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Valuation difference on available-for-sale securities | — | — | — | — | — | 
                                                930,180,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                930,180,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                868,442,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                868,442,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Foreign currency translation adjustment | — | — | — | — | — | 
                                                93,375,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                -3,202,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Remeasurements of defined benefit plans | — | — | — | — | — | 
                                                889,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                1,067,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Valuation and translation adjustments | — | — | — | — | — | 
                                                1,024,444,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                930,180,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                868,442,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                866,306,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Non-controlling interests | — | — | — | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                29,151,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Net assets | 
                                                270,018,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -198,939,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                60,383,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                930,180,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,303,843,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                4,387,975,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                4,324,272,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,363,531,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                93,375,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,024,444,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,303,843,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                930,180,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -105,198,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,394,092,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,988,608,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,198,003,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,198,003,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,135,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -198,939,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,091,185,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                930,180,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                889,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                64,364,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                4,672,807,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -198,939,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,198,003,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                4,622,372,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                868,442,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,726,914,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,198,003,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,804,365,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                866,306,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                868,442,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,533,904,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,501,457,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -198,939,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,303,843,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                29,151,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,088,106,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -3,202,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,067,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,135,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,303,843,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                301,092,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                868,442,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -34,454,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                391,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                68,346,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -198,939,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                4,608,824,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,296,446,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -198,939,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,262,383,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,296,446,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,193,904,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,135,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,310,015,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,296,446,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                6,031,949,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,228,248,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,198,003,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,432,595,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,303,843,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                4,735,502,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,198,003,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                5,871,207,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,303,843,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Liabilities and net assets | — | — | — | — | — | 
                                                8,819,595,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                7,596,749,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                7,984,847,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                9,071,873,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |